Mass limit for the standard model Higgs boson with the full LEP I ALEPH data sample

The reaction e⁺e⁻ → HZ^∗ is used to search for the standard model Higgs boson in the $H\nu \nu$ and the Hℓ⁺ℓ⁻ channels. The data sample corresponds to about 4.5 million hadronic Z decays collected by the ALEPH experiment at LEP from 1989 to 1995 at centre-of-mass energies at and around the Z peak. Three candidate events are found in the Hμ⁺μ⁻ channel, in agreement with the expected background from the electroweak process e⁺e⁻$\ell +\ell -qq$. This search results in a 95% C.L. lower limit on the Higgs boson mass of 63.9 GeV/c².